1. Classification of PCB Board Copper Clad Laminate
PCB board copper clad laminates consist of three components: copper foil, reinforcing materials, and adhesives. Sheets are generally classified based on reinforcement and adhesive types, or by their specific properties.
1. Classification by Reinforcing Materials
The commonly used reinforcing materials for PCB board copper-clad laminates include alkali-free glass fiber products (such as glass cloth and glass mat) or paper (such as wood pulp paper, bleached wood pulp paper, lint paper), among others. Consequently, PCB board copper clad laminates can be categorized into two main types: glass cloth-based and paper-based.
2. Classification by Adhesive Type
PCB foil-clad laminates utilize various adhesives such as phenolic, epoxy, polyester, polyimide, and PTFE resin. Consequently, PCB foil-clad laminates are categorized accordingly into phenolic resin type, epoxy resin type, polyester resin type, polyimide resin type, and PTFE resin type.
3. Classification by Base Material Characteristics
Based on the base material’s burning characteristics in flame and after removal from the fire source, laminates can be divided into general-purpose and self-extinguishing types. They can also be categorized as rigid or flexible based on their bending properties. Furthermore, depending on the substrate’s working temperature and environmental conditions, laminates can be classified as heat-resistant, anti-radiation, high-frequency PCB board foil-clad boards, etc. Additionally, special-purpose laminates include prefabricated inner layer foil-clad laminates and metal-based foil-clad laminates, which can further be categorized by the type of foil used, such as copper, nickel, silver, aluminum, and beryllium copper foil.
4. Standard Models of PCB Board Foil-Clad Laminates
Commonly used models for PCB board foil-clad laminates are specified in GB4721-1984. These models typically use a combination of five English letters: “C” denotes clad copper foil, followed by letters representing the binder resin type (e.g., PE for phenolic, EP for epoxy), and letters indicating the reinforcing material (e.g., CP for cellulose fiber paper, GC for alkali-free glass fiber cloth). Additional digits may follow to denote variations in product performance.
2. Manufacturing Method of Copper Clad Laminate for PCB Board
The manufacturing process of copper clad laminate for PCB boards primarily involves three steps: resin solution preparation, reinforcement material dipping, and compression molding.
1. Raw Materials for Manufacturing Copper Clad Laminates for PCB Boards
The main raw materials used in copper clad laminates include resin, paper, glass cloth, and copper foil.
– Resins: Phenolic, epoxy, polyester, and polyimide resins are commonly used. Phenolic resin, formed by the polycondensation of phenols and aldehydes in acidic or alkaline conditions, is predominant in paper-based PCB board foil-clad laminates. Epoxy resin, known for its excellent bonding and electrical properties, is primarily used in glass cloth-based PCB board foil-clad laminates.
– Impregnated Paper: Types include cotton lint paper, wood pulp paper, and bleached wood pulp paper, each offering different properties such as resin permeability, mechanical strength, and appearance improvement.
– Alkali-Free Glass Cloth: Used as a reinforcement material in glass cloth-based PCB board foil-clad laminates, with specific standards governing alkali content to ensure suitability for high-frequency applications.
– Copper Foil: Typically made from copper, with options for rolled or electrolytic types depending on conductivity, solderability, and adhesion to the substrate. Surface treatments like roughening or coating further enhance performance characteristics.
2. Manufacturing Process of Copper Clad Laminate
The process involves copper foil lamination, thermoforming, cutting, inspection, and packaging. Resin solution preparation occurs in reactors, with specific formulations tailored to the type of laminate being produced. Dipping of reinforcement materials follows, using horizontal or vertical dipping machines depending on material type. Dried and inspected materials are then ready for further processing into PCB boards.
